Most e-mail traffic involves one sender (i.e., the address specified in the From field) and one recipient (i.e., the address specified in the To field). In some cases, multiple recipients are specified using the To, Cc, and/or Bcc fields. Generally speaking, however, bulk or transactional e-mail is sent on a one-to-one basis for the sake of deliverability (i.e., the likelihood of the recipient's ISP to deliver the e-mail) as well as the recipient's privacy.
Typically, a sending application composes the content for an e-mail and passes the content to an agent called a mail transport agent (MTA). The MTA on the sender's side calls the recipient's domain as specified in the recipient's e-mail address. The sending MTA connects to the receiving MTA sitting behind the recipient's domain and then pushes the message across the connection. If the message cannot be delivered, a bounce may be generated. In response to the bounce, the sending MTA may retry or give up.
Message delivery may fail for a variety of reasons. The recipient's e-mail address may be abandoned by its user, reclaimed by its host (e.g., due to prolonged inactivity), canceled by its user (e.g., along with cancelation of service with the host), or otherwise deactivated for any number of potential reasons. The host of the recipient's domain may be temporarily inaccessible due to network problems or problems with hardware and/or software at the host's e-mail servers. In some cases, delivery may be significantly delayed by the host (e.g., for hours or days) due to transient problems or host policies.
Online merchants typically maintain only one e-mail address for each customer account. Therefore, if a message sent by the merchant bounces back, the merchant may have no other way to contact the customer electronically. For the many reasons discussed above, the message may not be available to the customer at the e-mail address associated with the customer's account within a reasonable amount of time after the message has been sent by the merchant. Some types of messages, such as advertisements or solicitations, may not be time-critical for the customer. However, detrimental consequences may follow if other types of messages, such as order confirmations, are not received promptly by the customer.
Accordingly, it is desirable for senders of e-mail (e.g., merchants) to have reliable techniques for contacting recipients (e.g., customers).
While embodiments are described herein by way of example for several embodiments and illustrative drawings, those skilled in the art will recognize that embodiments are not limited to the embodiments or drawings described. It should be understood, that the drawings and detailed description thereto are not intended to limit embodiments to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope as defined by the appended claims. The headings used herein are for organizational purposes only and are not meant to be used to limit the scope of the description or the claims. As used throughout this application, the word “may” is used in a permissive sense (i.e., meaning “having the potential to”), rather than the mandatory sense (i.e., meaning “must”). Similarly, the words “include,” “including,” and “includes” mean “including, but not limited to.”